SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '8c3b6e89437cf0daa89179c1887861af79ca4d4be5b82439f35d7d874ca1fb2c' 
  AND token = 'lf8i5Vg1zSMVH5ESQL4dJG1wUeDEaZkAq8XcbVcUdJY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}